Red Faction 5 (un-confirmed title) is an upcoming game and to be the fifth installment of the franchise. Considering the story is probably going to be continuing on Darius Mason or starting a new one that continue of previous timeline.
In April 2013, an Austrian computer gaming publisher called Nordic Games had purchased the IP for Red Faction (and Darksiders) from the bankrupt THQ and so they will carry on the series at some point. Future installments will not be developed by Volition anymore. [1]
However, a fan base is organizing. Demanding another sequel rather than a reboot with idea coming from the community. [2], [3]